Needle assembly

ABSTRACT

A needle assembly is disclosed, for use with an injection device. The needle assembly comprises a needle hub ( 20 ) having a needle ( 22 ) and a needle shield ( 40 ) arranged for relative axial movement with respect to the needle hub, between a retracted position in which the tip of the needle projects beyond a forward end of the shield and an extended position in which the tip of the needle does not project beyond the forward end of the shield. The needle shield ( 40 ) is axially biased towards the extended position. The needle shield ( 40 ) is further arranged to be torsionally biased for relative rotational movement with respect to the needle hub ( 20 ).

This invention relates to a needle assembly, and in particular, but notexclusively, to a single-use disposable needle assembly.

Injection devices, such as the Owen Mumford Autopen®, are commonly usedby patients to self-administer injections of medicament. Such devicesare typically provided in a pen-like body which contains, defines orreceives a cartridge or syringe of medicament. The injection devicegenerally comprises a delivery mechanism which is arranged to dispensethe medicament via a needle in response to a user pressing a button ortrigger.

As many such injection devices are arranged to be either reusable (i.e.the cartridge of medicament can be replaced) or to deliver a pluralityof separate injections until the medicament within the device has beenfully consumed it is common to arrange the device to receive adisposable, single-use, needle (which may be referred to as a “penneedle”). It is known to provide such needles as a needle assembly whichincludes both a hub, which carries the needle and is arranged to beremovably attached to the device (or syringe of the device) in use, anda shield member which is arranged to cover the needle prior to and/orafter use to reduce the risk of accidental needle-stick injuries duringuse. One such arrangement is, for example, disclosed in Published USPatent Application US2009/0259178 A1.

Whilst it may be desirable to provide a pen needle assembly whichincludes a shielding arrangement this must be balanced with therequirement that a pen needle is generally a disposable single usearticle. Thus, it would be advantageous if a pen needle assemblyincluding a needle shield did not significantly increase the part-countand/or complexity of the needle assembly and/or any associated packaging(which must generally maintain the sterility of the needle assemblyprior to use). At least some embodiments of the invention seek toprovide an improved needle assembly which may help to address some ofthese problems.

According to one aspect of the invention, there is provided a needleassembly, for use with an injection device, the needle assemblycomprising:

a needle hub having a needle;

a needle shield arranged for relative axial movement with respect to theneedle hub, between a retracted position in which the tip of the needleprojects beyond a forward end of the shield and an extended position inwhich the tip of the needle does not project beyond the forward end ofthe shield, the needle shield being axially biased towards the extendedposition; wherein

the needle shield is further arranged to be torsionally biased forrelative rotational movement with respect to the needle hub.

It will be appreciated that references to the forward end (or direction)of the needle assembly (or components thereof) refer to the end of theneedle assembly which is intended to face the injection site in use.

The needle hub may be configured to be attachable to an injectiondevice. For example, the needle hub may be provided with an internalscrew thread. The needle assembly may typically be a single use,disposable, item (which may for example be used with a reusableinjection device).

It will be appreciated that the needle shield is arranged to preventaccidental needle stick injuries before and/or after use. The needleassembly may lock the needle shield after use to prevent injuries and/orre-use of the needle assembly.

The needle assembly may have a spring member which is arranged to bothtorsionally and axially bias the needle shield relative to the needlehub. For example, the spring member may be a coil spring. Using a singlespring member to actuate both rotational and axial movements of theneedle shield relative to the needle hub may reduce the part-count andor overall complexity of the needle assembly. For example, the needleassembly according to some embodiments may advantageously consist ofonly three parts.

The needle shield and needle hub may be provided with cooperatingfeatures for controlling the relative movement thereof. The cooperatingfeatures may be configured such that relative rotational movement of theneedle shield relative to the needle hub is prevented until the needleshield moves towards the retracted position. For example, thecooperating features may be arranged such that the axial bias must becompressed before the rotational bias may rotate the shield. The needleshield may be initially held against the torsional bias by thecooperating features. The cooperating features may be arranged such thataxial movement of the needle shield relative to the needle hub releasesthe needle shield for automatic rotational movement under the torsionalbias.

The cooperating features may be configured such that in an initialposition relative rotation of the needle shield and needle hub islimited to a first rotational alignment. In the initial position theshield may be in its extended position.

The cooperating features may further be configured such that axialmovement of the needle shield rotationally releases the needle shieldand needle hub to allow relative rotation. The axial movement may betowards the retracted position. The relative rotation (after release)may be in the biased direction toward a second rotational alignment.

The cooperating features may be further configured such that upon returnof the needle shield to the extended position the rotational biasprevents return of the needle shield and needle hub to said firstrotational alignment. Thus, the cooperating features may retain theneedle shield and needle hub in said second rotational alignment. Uponreturn of the needle shield to the extended position further relativeaxial movement may be prevented by an axial stop. For example, thetorsional bias may provide relative rotational movement between the huband shield which aligns the cooperating features with the axial stop.

The cooperating features may comprise cooperating formations. Thecooperating features may, for example, comprise a track associated withone of the needle hub or the needle shield and a cooperating projectionassociated with the other of the needle hub or the needle shield. Theprojection may be a radial extending projection.

For example an outwardly radially extending projection may be providedon the needle hub. The track may be formed on an inner surface of theneedle shield. This may, for example, enable the needle hub to becontained within the needle shield.

The projection may comprise a resiliently deformable leg. In use, theleg may be displaced to allow relative rotational movement of the needleshield relative to the needle hub. A portion of the track may comprise aramp or cam surface arranged to displace the leg. For example, the rampor cam surface may be arranged to allow the projection to move between afirst and second track section (for example, by rotation under the forceof the torsional bias).

A plurality of said cooperating features (for example a plurality ofprojections and cooperating tracks) may be provided at circumferentiallyspaced locations. A plurality of cooperating features may, for example,provide improved stability between the needle hub and needle shield.

The needle assembly may be provided with a textured surface arranged toengage the skin during use. Such textured surfaces may act to mask theinjection pain. Thus, a forward facing surface of the needle shield maycomprise a textured surface. The textured surface may surround anaperture in the forward face of the needle through which the needleprojects in use. The textured surface may comprise a plurality offorwardly projecting spikes. For example the spikes may be arranged inat least one concentric ring around the aperture.

Advantageously, providing the textured surface on the needle shieldallows the rotation provided by the torsional bias during injection useto cause the textured surface to rotate against the skin. In embodimentsof the invention the shield rotates under the torsional bias as theshield is retracted. The forward surface of the needle shield may bearranged to rotate whilst in contact with the skin prior to the needleprojecting beyond the shield (to pierce the skin) and, thus, provides amasking stimulus. This is particularly so where the forward surface istextured.

The needle hub and needle may be fully contained within the needleshield when the shield is in the extended position. This may enable theouter surface of the needle shield to be the main sterile barrier forthe needle assembly.

According to another aspect of the invention, there is provided a needleassembly, for use with an injection device, the needle assemblycomprising:

a needle hub having a needle;

a needle shield arranged for relative axial movement with respect to theneedle hub, between a retracted position in which the tip of the needleprojects beyond a forward end of the shield and an extended position inwhich the tip of the needle does not project beyond the forward end ofthe shield; and wherein

the needle hub and needle shield are configured such that, when theneedle shield is in the extended position, the rearward end of theneedle hub is forward of the rearward end of the needle shield.

The needle shield may typically be axially biased towards the extendedposition (and may, for example, additionally include one or morefeatures from the above embodiments).

The needle shield may be longer in the axial direction than the combinedaxial length of the needle hub and needle. It will be appreciated thatthe axial direction of the needle assembly, and components thereof, willgenerally be the direction in which the needle is orientated.

The needle shield may extend from a substantially closed forward face.The closed forward face may include an aperture, through which theneedle extends in use. The needle shield may extend to a substantiallyopen rearward face.

The needle hub may be captive between the forward and rearward faces ofthe needle shield. In other words, the needle hub and needle shield maybe arranged to slide axially relative to one another but the needle hubmay be arranged such that it cannot move beyond, or be removed from, theinterior of needle shield. It will be appreciated that the interior ofthe needle shield may be defined by the forward and rearward faces andside walls of the needle shield and the outer. The needle hub and needleshield may be arranged such that the needle hub and needle are entirelybetween the faces of the needle shield when the shield is in theextended position.

At least one of the faces of the needle shield may be provided with aremovable closure. The closure may be arranged to be removed prior touse by the end user. The closure may provide a sterile seal. The closuremay be a “tear-off” flexible membrane. Alternatively, the closure may bea resilient member or cap.

The needle shield may be provided with a stop proximal to its rearwardend to delimit the range of relative axial movement between the needleshield and needle hub. The needle shield may further be provided with astop at its forward end (for example the forward stop could simplycomprise the inner surface of the closed front face). The, or each, stopmay cooperate with a corresponding feature of the needle hub. Thecooperating feature could, for example, comprise a rearward or forwardshoulder of the needle hub.

The needle shield defines a continuous outer sidewall (extending betweenthe forward and rearward faces) which encloses the needle hub. Thesidewall may be defined by a continuous circumferential surface. Thesidewall may provide a sterile outer barrier around the needle andneedle hub prior to use (such that only the forward and rearward facesneed be provided with a sterile seal). The sidewall may additionallymask or hide the needle from the user (which is particularlyadvantageous, for example, for users with needle phobia).

The needle assembly may be packaged in a flexible airtight wrapping. Forexample the wrapping may be a “flow-wrap” type packaging (which may alsobe referred to as a crimp seal wrapping). The flexible wrapping may besterile. The flexible wrapping may be tearable by the end-user. The useof such a simple packaging arrangement is not generally possible withexisting needle assemblies due to the risk of the needle piercing thepackaging resulting in needle stick injuries and/or loss of sterility.However, in embodiments of the invention the needle is, prior to use,captive within the needle shield and cannot be moved beyond the initialposition as no portion of the needle or hub extends beyond the rear ofthe needle shield (to provide a surface which could push the needleforward relative to the needle shield).

The needle assembly may further comprise a removable cap member arrangedto seal the needle assembly prior to use. The cap member may comprisefirst and second axially spaced apart covers configured in use to closethe end faces of the needle assembly. Thus, if the needle shield formsthe main sterile barrier the cap may act to close the needle shield.

This may be advantageous in its own right, thus according to a furtheraspect of the invention there is provided a needle assembly for use withan injection device, the needle assembly comprising: a needle hub havinga needle; a needle shield arranged for relative axial movement withrespect to the needle hub and a removable cap comprising first andsecond axially spaced apart covers configured in use to close the endfaces of the needle assembly. The needle hub and needle may be fullycontained within the needle shield when the shield is in the retractedposition.

The cap may be substantially U-shaped. The covers may be substantiallyradially extending. The covers may sealingly engage the radial end facesof the needle assembly (for example the radial end faces of the needleshield of the needle assembly). The cap may be arranged toengage/disengage the needle assembly in a radial direction.Advantageously, this may avoid any axial force being applied which mightact to pull the needle shield/needle hub apart during removal.

The cap may be arranged to resiliently engage the needle assembly. Forexample the cap may snap fit onto the needle assembly. This may, forexample, enable the cap to be re-engaged with the needle assembly afteruse (for example to re-seal and/or protect against needle injuries).

Needle assemblies according to embodiments of the invention may beprovided as a plurality of disposable needles such that a user has aconvenient supply and/or can track usage. According to a further aspectof the invention there is provided a kit comprising: a plurality ofneedle assemblies in accordance with an embodiment; and a storage traycomprising a plurality of recesses each configured to removably receivea needle assembly. Each needle assembly may be sealingly received into arecess prior to use. Thus, a sterile seal may be provided between thetray and needle assembly without the need to provide a separate sterileseal on that portion of the needle assembly. Thus, for example, only asingle individual sterile seal may be required on each needle assembly.

Thus, according to a further aspect of the invention there is provided amethod of packaging a plurality of needle assemblies, the methodcomprising: sealingly engaging a first end of each needle assembly intoa tray; and individually sealing the second end of each needle assembly.The method may further comprise the step of sterilising the plurality ofneedle assemblies and tray. For example, the assembled tray and needlesmay be subjected to gamma irradiation.

Whilst the invention has been described above with reference to a numberof embodiments and aspects it is to be understood that it includes anyinventive combination of the features set out above or in the followingdescription or drawings.

Specific embodiments of the invention will now be described in detail,by way of example only, and with reference to the accompanying schematicdrawings in which:

FIG. 1 shows a three dimensional representation and cross section of aneedle assembly and packaging in accordance with an embodiment of theinvention;

FIG. 2 shows three-dimensional views and a front view of a needle hubcomponent for use in an embodiment;

FIG. 3 shows three-dimensional views, a front view, a top view and across section of a needle shield component for use in an embodiment;

FIG. 4 is a cross sectional representation of the needle assemblyaccording to an embodiment showing the sequential relative movement ofthe needle hub and needle shield during use;

FIG. 5 shows a three dimensional view of needle assembly according to analternative embodiment in a sequence of positions during use;

FIG. 6 shows three-dimensional views and a top view of a needle hubcomponent for use in the embodiment of FIG. 5;

FIG. 7 shows three-dimensional views, a front view, a top view and across section of a needle shield component for use in the embodiment ofFIG. 5;

FIG. 8 is a cross sectional representation of the needle assembly ofFIGS. 5 to 7 according to an embodiment showing the sequential relativemovement of the needle hub and needle shield during use;

FIG. 9 shows an alternative packaging arrangement for a needle assemblyin accordance with an embodiment;

FIG. 10 shows a further packaging alternative for needle assembliesaccording to the embodiments of the invention;

FIG. 11 shows a needle assembly and cap according to an embodiment ofthe invention.

Front as used herein will be understood to refer to the end of the penneedle assembly (or components thereof) which is, in use, pointed at theskin. Rear as used herein will be understood to refer to the end of thepen needle assembly (or components thereof) which is, in use, distalfrom the skin. Forward and rearward will, likewise, be understood torefer to the directions orientated towards the front and rear of the penneedle assembly.

A needle assembly 10 is shown in FIG. 1 contained within a flow wrapsterile packaging 100 in a typical configuration in which the needleassembly 10 may be initially supplied to a user. The needle assembly 10includes a needle hub 20 which carries a needle 22 (which may be adouble ended needle with a forward projecting portion for piercing theskin and a rearward projecting end for piercing the septum of aninjection device). An interconnecting arrangement such as an internalthread 24 is provided on the hub 20 to allow attachment of the needleassembly to an injection device. It may be noted that in the embodimentof FIG. 1 the hub 20 has a two part construction but it will beappreciated that this is an optional arrangement (for example in theembodiment of FIG. 2 the hub 20 is formed as a single moulding). Theneedle assembly 10 further comprises a needle shield 40 which isrelatively moveable with respect to the needle hub between the extendedposition shown in FIG. 1 (in which the needle is covered and which may,therefore, alternatively be referred to as a shielded position) and aretracted position in which the needle 22 will project beyond theforward surface 60 of the needle shield 40 through the aperture 62 (andwhich may, therefore, alternatively be referred to as a deliveryposition). A coil spring 30 is provided between the hub 20 and shield 40and, as will be explained in further detail below, is arranged toaxially bias the shield 40 towards the extended position and totorsionally bias the shield 40 relative to the hub 20. In the suppliedstate it may be noted that the needle hub 20 and needle 22 are bothfully contained within the needle shield 40 as the needle shield extendsboth forward beyond the tip of the needle and rearward beyond the rearsurface of the hub 20. This ensures that the needle and hub are fullyprotected by the shield and enables the use of a simple flow wrap typepackaging without the need to additionally protect/enclose the needle.

The hub 20 is shown in isolation in FIG. 2. As noted above, in thisembodiment the hub 20 is formed as a single moulding and includes aneedle support 23 into which the needle 22 is permanently attached (forexample by bonding or plastic welding). The needle 22 is standard andhas been omitted from FIGS. 2 to 8 for clarity (since the key featuresof the embodiments are formed in the needle hub 20 and shield 40).

The needle hub 20 is provided with features, in the form of radiallyoutwardly splaying legs 25 which project from a radial shoulder 24. Thelegs 25 cooperate with corresponding features on the needle shield tocontrol the relative movement of the needle shield 40 and needle hub 20.As will be explained below, the legs are inwardly resilientlydeformable. It will be appreciated that whilst the illustratedembodiment has three circumferentially distributed legs 25 a, 25 b and25 c more or less legs may be provided as convenient (balancing therequirements of stability of the needle hub 20 relative to the needleshield 40 and the overall manufacturing complexity of the needleassembly 10).

The needle shield 40 is shown in FIG. 3 and comprises a generallycylindrical outer body having a forward surface 60 (which abuts theusers skin in use) and an open rearward end into which the needle hub 20is received. An aperture 62 is provided at the centre of the forwardsurface 60 through which the needle 22 will project during use. Theinner surface of the shield 40 is provided with cooperating features forengaging with the legs 25 of the hub 20. As best seen in FIG. 3(e) eachof the cooperating features is formed of a track 50(a), 50(b) and 50(c)arranged and configured to receive the respective leg 25. Each trackcomprises a first slot 52 which includes a ramp section 53, an axiallyextending rib 54 and a second slot 56. The operation of the track 50 andlegs 25 will be described in further detail below.

The forward facing surface 60 of the shield 40 has a textured surface.The textured surface provides nerve stimulation to the skin immediatelysurrounding the injection site during use so as to mask the pain of theneedle penetration. In particular, the textured surface may be formed bya series of spikes which are sized so as to provide sufficientstimulation of the skin without piercing the skin surface and may forexample have dimensions of approximately 1 mm×1 mm with a 23° chamferangle. In the illustrated example the spikes are arranged in a first 64and second 66 concentric ring surrounding the needle aperture 62.

FIG. 4 shows the sequential operation of the needle apparatus in crosssection (in particular to illustrate the interaction of the cooperatingfeatures). FIG. 4(a) shows the initial position, with the hub 20 in afirst rotational alignment relative to the needle shield 40. The legs 25are positioned within the first slot 52 of the track 50 and the spring30 is biasing the hub 20 and shield 40 to their extended positions. Itwould be noted that the readily inward projection 55 provided at the endof the rib 54 engages the rearmost surface of the hub 20 so as to act asa stop which delimits the relative axial movement of the shield 40 andthe hub 20. Thus, the hub 20 is retained captive within the shield 40.In this position, the coil spring 30 is also providing a torsional biason the needle hub 20 but rotational movement of the hub 20 relative tothe shield 40 is prevented as the width of the first slot 52 closelymatches the width of the legs 25 and the slot is of sufficient depth toretain the legs therein. Thus, the legs 25 and first slot 52 of thetrack 50 hold the hub 20 and shield 40 in the first rotationalalignment. As the injection device is pressed against the users skinand/or the syringe of the injection device is moved forward there isrelative movement between the needle hub 20 and the needle shield 40towards the retracted position of the needle shield as shown in FIG.4(b). The legs 25 of the hub 20 initially travel along the first slot 52and are resiliently deflected progressively inwardly by the ramp 53formed in the slot 52 as they reach the forward axial end of the slot52. This allows the legs to be released from the slot 52 freeing the hub20 for rotation under the torsional force of the coil spring 30 towardsthe rib 54. The rib 54 provides a rotational stop to limit the extent ofthe relative rotation between the hub 20 and shield 40. The rib 54,therefore, defines (in cooperation with the leg 25) the secondrotational alignment of the hub 20 and shield 40.

As the device is removed from the skin the compressed spring 30 axiallybiases the needle shield 40 and needle hub 20 apart so as to return theneedle shield to its extended position, as shown in FIG. 4(c). Thus, theshield 40 returns to an axial position in which the needle is fullyenclosed within the shield 40. Due to the torsional bias of the spring30 the hub 20 and shield 40 remain in their second rotational alignmentduring the retraction movement with the legs 25 abutting the ribs 54.When the shield 40 has reached a sufficiently extended position the legs25 move into alignment with the second slot 56 of the track 50. Due tothe shape and resilience of the legs (which are inwardly deformed afterleaving the first slot 52) the legs snap outwardly to be retained withinthe slot 56. The second slot 56 is formed with step sides and a flatbase to help retain the legs 25 therein. The legs 25 cannot deforminwards so prevent the spring from being compressed and lock the needlehub 20 into its rearward position after use. It will also be noted thatthe projection 55 is once again in alignment with the rearward edge ofthe hub 20 so that rearward movement of the needle hub 20 relative tothe needle shield 40 is also prevented.

A needle assembly 210 according to a further embodiment is shown in FIG.5 (with corresponding features generally indicated by reference numeralsincreased by 200). In this embodiment the needle hub 220 is providedwith an inner 221 and outer 223 circumferential walls (as seen in FIG.6) with the needle shield 240 received within the annular space definedbetween the walls. The coil spring may also be received within theannular slot defined between the inner wall 221 and outer wall 223 ofthe needle hub 220 to axially and torsionally bias the needle hub 220and needle shield 240. It will, however, be appreciated that the springmay alternatively be positioned on the inside of the inner wall 221.

As in the previous embodiment, the needle hub 220 is provided with aninternal thread 224 at its rearward end for attachment to an injectiondevice in use. In this embodiment the cooperating features of the needlehub 220 comprise 3 circumferentially spaced apart bosses 225 a, 225 band 225 c. The bosses project inwardly from the inner surface of theouter wall 223. A cut-out 227 may be provided in the inner wall 221adjacent to each boss 225 so as to provide a gap for the radially inwarddeflection of a latch member 251 on the needle shield 240 duringassembly of the needle assembly 210.

The needle shield 240 includes a forward skin facing surface 260 (whichmay include a textured surface such as that shown in the firstembodiment) and is provided with a central aperture 262 through whichthe needle connected to the needle hub 220 may project during use. Thecooperating features 250 a, 250 b and 250 c of the needle shied 240comprise a track which includes a first slot 252, a second slot 254 anda latch area 255. At the rearward end of the track the first 252 andsecond 254 slots are separated by a rib 253. The rib 253 protrudesradially inwardly and extends axially along part of the track 250. Aresiliently deformable tab 251 is provided at the rearward end of thefirst slot 252 and is arranged to deflect radially inward so as to passover the boss 225 when the shield 240 and hub 220 are initially broughttogether (so that the boss 225 can be positioned within the track 250).

FIG. 8 shows the operational sequence of the needle assembly 210according to a second embodiment. It may be noted that the coil springhas been omitted in these figures (purely for the purpose of clarity)and it will be appreciated that the spring would be provided between theneedle hub 220 and needle shield 240 in a similar manner to the firstembodiment so as to both rotationally and axially bias the components.In the initial position shown in FIG. 8(a), the boss 225 is positionedin the first slot 252 the coil spring biases the needle hub 220 andneedle shield 240 to the extended position and the boss abuts the tab251 to prevents over expansion or removal of the needle shield 240. Asthe needle shield 240 is pressed against the skin it moves towards theretracted position shown in FIG. 8(b) (compressing the coil spring).When moving towards this position the boss 225 passes beyond the axiallyextent of the rib 253 which separates the first slot 252 and second slot254 of the track 250. As such, the needle shield 240 may rotate up tothe needle hub 220 under the force of the torsional bias provided by thespring. This brings the needle shield 240 and needle hub 220 into thesecond rotational alignment when the boss 225 meets the side wall of thesecond slot 254. As the user removes the injection device from the skinthe needle shield 240 moves back towards its extended position under theforce of the axial bias of the coil spring as shown in FIG. 8(c). Axialmovement brings the boss 225 into alignment with the latch portion 255of the track 250. As the latch section 255 is positioned to the side ofthe second slot 254 the spring may further rotate the shield 240 in thebiased direction relative to the hub 220 such that the boss moves intothe latch section 255 (thus the hub 220 and shield 240 are in a thirdrotational alignment). In this position the needle shield 240 is lockedagainst further movement towards the retracted position (with axialmovement being blocked by the front and rear walls of the latch sectionof the track and the spring resisting rotation out of the latch).

FIG. 9 illustrates a method of providing a plurality of needleassemblies (which may be needle assemblies in accordance with anembodiment of the invention). The needle assemblies are provided in akit comprising a tray 300 formed with a plurality of recesses 310 eachof which is configured to receive a single needle assembly 10. Therecesses 310 are formed with a female profile corresponding to theforward end of the needle assembly 10. The recesses are intended tosealingly receive the needle assembly 10. Advantageously, in embodimentsof the invention the needle assembly may be arranged such that all ofthe interconnecting features are formed on the inside of the shieldmeans and the needle hub and needle are fully captive within the shieldduring storage. Thus, only the two end surfaces of the needle assembly10 need to be sealed and the outer body of the needle shield may act asa sterile barrier. This may both simplify packaging and reduce thenumber of component parts. In particular, when provided in the trayarrangement of FIG. 9 the needle assembly 10 may seemingly engage withthe tray 300 and a conventional “tear off” seal 400 may be provided onthe other end of the needle assembly. The provision of needle assembliesin a tray may also help the user to track the usage of their needleassemblies.

Alternatively, the needle assemblies may be individually wrapped asshown in FIG. 10 and may be provided as a strip 500 comprising aplurality of packaged needle assemblies 510.

Alternatively or additionally, the needle assembly 10 may be providedwith a cap 600 as shown in FIG. 11. The cap may be arranged to seal bothends of the device by having first 610 and second 620 spaced apartsealing members connected by an axial joining member 645. The sealingmembers 610 and 620 generally extend in a plane which is radial withrespect to the needle assembly (when the cap is engaged with theassembly). The sealing members may be tapered or splay outwardly (toassist removal/engagement between the cap and the needle assembly). Theinner surface of each of the end members 610 and 620 may be formed so asto resiliently engage the ends of the needle assembly 10. The needleassembly 10 may be easily removed from the cap by pulling the cap 600and needle assembly 10 apart in a transverse (generally radial)direction. As the removal is in the radial direction it will not applyany force in the axial direction on the components of the needleassembly. The needle cap 600 can resiliently engage the needle assembly10 such that it may be used both as a sealing member prior to use and ameans for recovering the needle assembly 10 prior to disposal (i.e., tohelp further avoid any risk of needle stick injuries). Whilst theembodiment shown has only a single cap 600 it will also be appreciatedthat a plurality of cap members 600 could be joined together in order tosupply a plurality of needle assemblies in a similar manner to theembodiment of FIG. 9.

Although the invention has been described above with reference to one ormore preferred embodiments, it will be appreciated that various changesor modifications may be made without departing from the scope of theinvention as defined in the appended claims.

For example, the needle assembly 210 of the second embodiment does notinclude an arrangement in which the needle hub 220 is fully containedwithin the needle shield 220. However, the skilled person will readilyappreciate that the function of the cooperating features of the needlehub in that embodiment could be used in an arrangement such as that ofthe needle assembly 10 220

1. A needle assembly, for use with an injection device, the needleassembly comprising: a needle hub having a needle; a needle shieldarranged for relative axial movement with respect to the needle hub,between a retracted position in which the tip of the needle projectsbeyond a forward end of the shield and an extended position in which thetip of the needle does not project beyond the forward end of the shield,the needle shield being axially biased towards the extended position;wherein the needle shield is further arranged to be torsionally biasedfor relative rotational movement with respect to the needle hub.
 2. Aneedle assembly as claimed in claim 1, further comprising a springmember which is arranged to both torsionally and axially bias the needleshield relative to the needle hub.
 3. A needle assembly as claims inclaim 1 or 2, wherein the spring member is a coil spring.
 4. A needleassembly as claimed in any preceding claim, wherein the needle shieldand needle hub are provided with cooperating features configured suchthat relative rotational movement of the needle shield relative to theneedle hub is prevented until the needle shield moves towards theretracted position.
 5. A needle assembly as claimed in any precedingclaim, wherein the needle shield and needle hub are provided withcooperating features configured such that: in an initial position, wherethe shield is in its extended position, relative rotation of the needleshield and needle hub is limited to a first rotational alignment, axialmovement of the needle shield towards the retracted positionrotationally releases the needle shield and needle hub to allow relativerotation in the biased direction toward a second rotational alignment.6. A needle assembly as claimed in claim 5, wherein the cooperatingfeatures are further configured such that upon return of the needleshield to the extended position the rotational bias prevents return ofthe needle shield and needle hub to said first rotational alignment andfurther relative axial movement is prevented by an axial stop.
 7. Aneedle assembly as claimed in any of claims 3 to 6, wherein thecooperating features comprise a track associated with one of the needlehub or the needle shield and a cooperating projection associated withthe other of the needle hub or the needle shield.
 8. A needle assemblyas claimed in claim 7, wherein the projection comprises a resilientlydeformable leg.
 9. A needle assembly as claimed in claim 8, wherein, inuse, the leg is displaced to allow relative rotational movement of theneedle shield relative to the needle hub.
 10. A needle assembly asclaimed in claim 9, wherein a portion of the track comprises a rampsurface arranged to displace the leg.
 11. A needle assembly as claimedin any of claims 3 to 10, wherein a plurality of said cooperatingfeatures are provided at circumferentially spaced locations.
 12. Aneedle assembly as claimed in any preceding claim, wherein a forwardfacing surface of the needle shield comprises a textured surface.
 13. Aneedle assembly as claimed in claim 12, wherein the textured surfacecomprises a plurality of forwardly projecting spikes.
 14. A needleassembly as claimed in any preceding claim, wherein the needle hub andneedle are fully contained within the needle shield when the shield isin the retracted position.
 15. A needle assembly, for use with aninjection device, the needle assembly comprising: a needle hub having aneedle; a needle shield arranged for relative axial movement withrespect to the needle hub, between a retracted position in which the tipof the needle projects beyond a forward end of the shield and anextended position in which the tip of the needle does not project beyondthe forward end of the shield; and wherein the needle hub and needleshield are configured such that, when the needle shield is in theextended position, the rearward end of the needle hub is forward of therearward end of the needle shield.
 16. A needle assembly as claimed inclaim 15, wherein the needle shield is longer in the axial directionthan the combined axial length of the needle hub and needle.
 17. Aneedle assembly as claimed in claim 15 or 16, wherein the needle shieldextends from a substantially closed forward face having an aperture,through which the needle extends in use, to a substantially openrearward face.
 18. A needle assembly as claimed in claim 17, wherein theneedle hub is captive between the forward and rearward faces of theneedle shield.
 19. A needle assembly as claimed in claim 17 or 18,wherein at least one of the faces is provided with a removable closure.20. A needle assembly as claimed in any of claims 15 to 19, wherein theneedle shield is provided with a stop proximal to its rearward end todelimit the range of relative axial movement between the needle shieldand needle hub.
 21. A needle assembly as claimed in any of claims 15 to21, wherein the needle shield has a continuous outer sidewall whichencloses the needle hub.
 22. A needle assembly as claimed in anypreceding claim, wherein the needle assembly is packaged in a flexibleairtight wrapping.
 23. A needle assembly as claimed in any precedingclaim, further comprising a removable cap arranged to seal the needleassembly prior to use, wherein the cap comprises first and secondaxially spaced apart covers configured, in use, to close the end facesof the needle assembly.
 24. A needle assembly for use with an injectiondevice, the needle assembly comprising: a needle hub having a needle; aneedle shield arranged for relative axial movement with respect to theneedle hub; and a removable cap comprising first and second axiallyspaced apart covers configured in use to close the end faces of theneedle assembly.
 25. A needle assembly as claimed in claim 24, whereinthe needle hub and needle are fully contained within the needle shieldwhen the shield is in the retracted position.
 26. A needle assembly asclaimed in claim 23, 24 or 25, wherein the cap member is substantiallyU-shaped.
 27. A needle assembly as claimed in any of claims 23 to 26wherein the cap member is arranged to resiliently engage the needleassembly.
 28. A kit comprising: a plurality of needle assemblies asclaimed in any preceding claim; a storage tray comprising a plurality ofrecesses each configured to removably receive a needle assembly.
 29. Akit according to claim 18, wherein each needle assembly is sealinglyreceived into a recess prior to use.
 30. A method of packaging aplurality of needle assemblies, the method comprising: sealinglyengaging a first end of each needle assembly into a tray; andindividually sealing the second end of each needle assembly.
 31. Themethod of claim 30, further comprising the sterilising the plurality ofneedle assemblies.